CLUTCH GRINDING NOISE / BH MISALIGNMENT

Just to be clear, we are talking about an A-833 here right?
#1, is ;are the retainer bolts the correct ones.Integral Washer-head with no extra washers, The underside of the washerhead is serrated to prevent backing out.
#2 is; Has the retainer been machined down from a different diameter? And is it still round, and concentric to the bearing, and was the entry bevel remachined onto it?
#3 is; The snap ring on the input bearing; is it the original one to the tranny? The snap ring that comes on the replacement bearing is always wrong, without exception.
#4, remove the retainer and pop it into the BH opening. Does it fit?
#5, Are you absolutely sure the flywheel is fully seated on the crank? If it was off, just a wee tiny bit, then the flywheel would wobble, sending your indicator into fits, just as you describe. And making it possible that all your efforts in centering it were for naught.It would then also hold the disc at an angle, and probably prevent the input from fully engaging.The same can be found on a flywheel that has been ground crooked, where the front and rear surfaces are not parallel.
#6 As to moving the BH around, don't forget, it can only move as far as the bolts allow it to. Sometimes you have to clearance the bolt-holes to make things happen.Furthermore the dowels are there to provide repeatability. They don't actually have to be there. There is nothing stopping you from leaving them out, which can make dialing it in so much easier. But you will have to re-dial it every time the BH comes off, or is loosened.. No biggie to me. You can weld up the aluminum holes, and drill through from the starter side, and put the original dowels back in.
#7, Are the two surfaces of the BH parallel?
#8, does the disc slide nicely on the input splines?
#9, Did you use a pilot tool to align the disc prior to sliding the tranny in.The plastic ones are notoriously poor fitting, requiring the installer to fudge the disc somewhat in the vertical direction.And if the pilot bearing is bad, the fudging gets fudged. I highly recommend the Magnum BB replacement pilot bearing,that registers into the Convertor hole. You can leave the old bushing in the crank, I did,with no problems.
#10, With a scalloped clutch it might be a good idea to install the PP and disc, except leave the PP bolts loose enough to to shift the disc around while the tranny slides in. Then tighten those PP bolts in the usual way.

And that's all I can think of for now.Good hunting!